1. Field of the Invention
This invention relates to the field of sanding devices to be used to smooth dry walls and the like. In particular, it relates to sanding apparatus having a pivotally mounted head capable of reaching and pressing flat against wall locations over a wide area, from those close at hand to those well beyond the reach of the operator, to sand away excess joint cement and to draw the particles of grit by vacuum into a water trap via an air lock.
2. The Prior Art
In sanding dry walls to remove excess joint cement or plaster, it is desirable to do so over a widely spaced areas of wall surface without the operator's having to move far from a fixed location and, in particular, having to climb a ladder to reach the upper part of the wall. In modern houses having cathedral ceilings, this requires attaching abrasive material to a head mounted on a pole.
The head has a flat surface across which is stretched a sheet of abrasive material, such as sandpaper, sanding screen, and other such sheets of material, and it is necessary to keep the flat surface as flat against the wall as possible, whether the location being sanded at any instant is rather close to the operator or is some distance away, high or low or to either side of the operator.
Romine, U.S. Pat. No. 4,697,389, describes a vacuum sander using sandpaper on a solid block attached to a pole. Neither the block nor the sandpaper has apertures that would permit dust and air to pass through, and so the block is surrounded by a shroud that draws in not only the dust created by sanding but a great deal of air from the surrounding area. This requires that the vacuum cleaner have a high capacity to move air, all of which, including that laden with dust, will directly enter the vacuum cleaner, since Romine does not provide a water filter.
Mehrer, U.S. Pat. No. 4,062,152, describes a vacuum sanding device in which a hollow pole connected to a vacuum source is mounted on a universal swivel in the sanding head. Openings formed in the pole adjacent the mount allow dust-laden air drawn through a sanding screen and through an apertured plate into a chamber surrounding those openings to enter the pole directly and be moved along to the vacuum source. Part of the walls of the chamber are defined by a somewhat flexible boot of special shape that allows the pole to be pivoted through a limited solid angle. As in the Romine patent, no water filtration is suggested by Mehrer.